Nobody is happy with this legislation, not even Airbnb and its hosts, whose scofflaw actions in San Francisco would finally be made legal. But because the company has been unwilling to help the city regulate its short-term rentals in order to preserve permanent affordable housing units in the city, the final legislation would be tough to enforce.

That’s why Sup. Jane Kim voted against the legislation yesterday at the board’s Land Use and Economic Development Committee meeting, according to an account by the Examiner, citing the city’s inability to enforce the legislation’s ostensible limit of 90 rental nights per year (it requires hosts to live in their units for 275 days per year).

Nonetheless, the committee voted 2-1 to send the measure on the full board, even though it still has significant organized opposition from both landlord and tenants groups, hotel owners and workers, Airbnb hosts who don’t want to register or pay taxes, and a wide variety of other activists, including those who originally helped forge city laws preventing apartments from being converted into tourist hotels.

Although the San Francisco Tenants Union helped crafted the legislation and was an early supporter, the group has since voiced concerns about many aspects of the legislation, which has grown steadily weaker from a tenant perspective, offering few protections for tenant-hosts and even being amended this month to require that landlords get notified when a tenant registers with the city as a host (making it less likely those hosts will actually register).

At least one of Chiu’s close advisors warned him over a year ago that this was a no-win endeavor for him — particularly as it comes to the board just a month before the end of his Assembly race against board colleague David Campos — and that appears to have been prescient advice.

Yes, someone needed to wade into this muck and mire, given that thousands of apartments in San Francisco have been taken off the market by Airbnb, which has even flouted city rulings that it collect and pay the hotel tax (which the company says it will finally start doing tomorrow [Wed/1]).

But the question facing supervisors next week will be what the city is getting from Airbnb and similar companies in exchange for legalizing their illegal business model, at a time when the city needs every affordable housing unit it can get for actual San Franciscans.